IEEE 519-2022 limits the harmonic current an installation injects at the PCC with three tables by voltage level. Each gives a limit per harmonic order range and a TDD, stepped by the Isc/IL ratio. They apply to the whole installation and not to a single piece of equipment.
Short answer
IEEE 519-2022 limits the harmonic current an installation injects at the PCC with three tables, according to the PCC voltage: Table 2 (120 V to 69 kV), Table 3 (above 69 kV up to 161 kV) and Table 4 (above 161 kV). In each one, the row depends on the Isc/IL ratio and the column on the harmonic order. The values are percentages of the maximum demand current IL, and the last column is the TDD.
How to read a table
Each table has five harmonic order ranges h and one TDD column. The rows depend on the Isc/IL ratio, which is explained in Maximum Demand Current IL and the Isc/IL Ratio. The values are the maximum harmonic current distortion, as a percentage of IL:
Table 2: 120 V to 69 kV
| Isc/IL | 2 ≤ h < 11 | 11 ≤ h < 17 | 17 ≤ h < 23 | 23 ≤ h < 35 | 35 ≤ h ≤ 50 | TDD |
|---|---|---|---|---|---|---|
| less than 20 | 4.0 | 2.0 | 1.5 | 0.6 | 0.3 | 5.0 |
| 20 to less than 50 | 7.0 | 3.5 | 2.5 | 1.0 | 0.5 | 8.0 |
| 50 to less than 100 | 10.0 | 4.5 | 4.0 | 1.5 | 0.7 | 12.0 |
| 100 to less than 1,000 | 12.0 | 5.5 | 5.0 | 2.0 | 1.0 | 15.0 |
| greater than 1,000 | 15.0 | 7.0 | 6.0 | 2.5 | 1.4 | 20.0 |
Table 3: above 69 kV up to 161 kV
| Isc/IL | 2 ≤ h < 11 | 11 ≤ h < 17 | 17 ≤ h < 23 | 23 ≤ h < 35 | 35 ≤ h ≤ 50 | TDD |
|---|---|---|---|---|---|---|
| less than 20 | 2.0 | 1.0 | 0.75 | 0.3 | 0.15 | 2.5 |
| 20 to less than 50 | 3.5 | 1.75 | 1.25 | 0.5 | 0.25 | 4.0 |
| 50 to less than 100 | 5.0 | 2.25 | 2.0 | 0.75 | 0.35 | 6.0 |
| 100 to less than 1,000 | 6.0 | 2.75 | 2.5 | 1.0 | 0.5 | 7.5 |
| greater than 1,000 | 7.5 | 3.5 | 3.0 | 1.25 | 0.7 | 10.0 |
Table 4: above 161 kV (only three rows)
| Isc/IL | 2 ≤ h < 11 | 11 ≤ h < 17 | 17 ≤ h < 23 | 23 ≤ h < 35 | 35 ≤ h ≤ 50 | TDD |
|---|---|---|---|---|---|---|
| less than 25 | 1.0 | 0.5 | 0.38 | 0.15 | 0.1 | 1.5 |
| 25 to less than 50 | 2.0 | 1.0 | 0.75 | 0.3 | 0.15 | 2.5 |
| 50 or more | 3.0 | 1.5 | 1.15 | 0.45 | 0.22 | 3.75 |
The tables show two trends. The lower the Isc/IL ratio, the lower the limit: a weak network tolerates less harmonic current from the user. And, in each row, the high orders have lower limits than the low ones. The same stepping repeats at higher voltage, with smaller values.
The notes that accompany the tables
The three tables carry the same notes:
- Even harmonics. For orders less than or equal to 6 (h ≤ 6), even harmonics are limited to 50 % of the table values.
- Direct current. Current distortions that produce a DC offset, such as those of half-wave converters, are not allowed.
- Generation. Generation facilities are limited to the values of the lowest-ratio row, regardless of their actual Isc/IL, unless another standard with applicable scope covers them.
In addition, each table defines Isc as the maximum short-circuit current at the PCC and IL as the maximum demand load current at the PCC under normal load operating conditions.
An edge case. In Tables 2 and 3, the ranges appear as “100 to less than 1,000” and “greater than 1,000”. The text does not say in which one a ratio exactly equal to 1,000 falls. If your installation is at that value, agree with the utility on which row applies.
The three factors that multiply the table
The tables give a base value. Clauses 5.3, 5.4 and 5.5 define how a measurement is compared with it, with three statistical criteria at the PCC:
| Measurement value | Period | Must be less than |
|---|---|---|
| 99th percentile of 3 s values | Each day | 2.0 times the table value |
| 99th percentile of 10 min values | Each week | 1.5 times the table value |
| 95th percentile of 10 min values | Each week | The table value |
Take the example of a 13.2 kV installation with an Isc/IL of 30 (“20 to less than 50” row of Table 2): the 5th and 7th harmonics fall in the range 2 to less than 11, with a limit of 7.0 %. The weekly 95th percentile of 10 min must be less than 7.0 %, the weekly 99th percentile less than 10.5 % and the daily 99th percentile of 3 s less than 14.0 %. These are table figures multiplied by the factors, not measurement results.
How those percentiles are obtained is explained in 95th and 99th Percentiles in IEEE 519: How It Is Evaluated, and how to measure in Measuring Harmonics for IEEE 519: the 12-Cycle Window.
What the tables do not cover
- Interharmonics. The tables apply to currents with frequencies that are integer multiples of the fundamental frequency. For interharmonics, the standard indicates that limit values are to be developed case by case from Annex A.
- Inverter-based generation. For installations with inverter-based resources, the standard refers to other standards (IEEE 1547 and IEEE 2800). That boundary is explained in IEEE 519 with Inverters and Generation: When It Applies.
- Raising limits with filters or more pulses. Clause 5.6 allows individual limits to be raised with multipliers if low orders are reduced. It is covered in IEEE 519 Limit Multipliers for Pulse Number and Filters.
How it relates to the harmonic study
The harmonic study uses these tables as the acceptance criterion: it calculates the harmonic currents the installation would inject at the PCC and compares them with the corresponding row. For the origin of those currents in drives, see Variable Frequency Drive Harmonics. The definition of THD and TDD is in THD: What It Is, How It Is Calculated and IEEE 519 Limits.
The limit applies at the point of common coupling (see PCC in IEEE 519: Where Harmonic Limits Apply) and the voltage limit that falls on the utility is in IEEE 519-2022 Voltage Harmonic Limits at the PCC. To compare a spectrum with Table 2 (up to 69 kV) you can use our free harmonic distortion THD and TDD tool.
We help you verify your limits
At Tiza Group we carry out power quality studies, in Colombia, or elsewhere on request: we determine your PCC, your Isc/IL ratio and the IEEE 519-2022 row that applies to you, and tell you what measures to take if the installation approaches the limit.
Related guides
- Maximum Demand Current IL and the Isc/IL Ratio
- IEEE 519-2022 Voltage Harmonic Limits at the PCC
- IEEE 519 Limit Multipliers for Pulse Number and Filters
- IEEE 519 with Inverters and Generation: When It Applies
- 95th and 99th Percentiles in IEEE 519: How It Is Evaluated
References
- IEEE Std 519-2022, IEEE Standard for Harmonic Control in Electric Power Systems: clauses 5.3, 5.4 and 5.5 with Tables 2, 3 and 4 (limits, notes and statistical factors); clause 5.6 and Table 5 (multipliers); clause 3.1 (IL and short-circuit ratio).
Frequently asked questions
Do the Table 2 limits apply to each drive or to the whole plant?
To the whole installation, seen from the PCC. Clause 5.3 says these limits are not used to evaluate an individual nonlinear load, but the installation that contains those loads.
What does it mean that even harmonics are limited to 50 %?
The note to the tables indicates that, for orders h less than or equal to 6, even harmonics are limited to 50 % of the table values. That is, the 2nd, 4th and 6th have half the limit of the range.
Does a generation plant follow the row that corresponds to its Isc/IL?
No. The note to the tables limits generation facilities to the values of the lowest-ratio row (less than 20 in Tables 2 and 3, less than 25 in Table 4), regardless of their actual Isc/IL, unless another standard with applicable scope covers them.